The present invention relates to packaging machines, and more particularly to a machine for filling a fluid food or similar contents into tubular containers having a bottom and thereafter closing all upper end portion of each container to form a top portion thereof and complete a sealed container as filled with the contents.
Packaging machines are known which comprise, as arranged along a path of transport, a filling device for filling a specified amount of contents into tubular containers having a bottom, a top breaker for folding an upper end portion of the filled container, a top heater for heating the folded end portion, and a top sealer for bonding the end portion under pressure.
Some kinds of coffee, juice, milk, etc. are liable to froth. When such a liquid is discharged from the filling nozzle, the impact of fall onto the bottom of the container and a continuous increase in the amount of liquid in the container to the specified quantity to be filled agitate the contents to produce froth.
If a large amount of froth is produced, the froth will be forced out from the upper end of the container, making it difficult for the top breaker to fold the container upper end portion. Another problem commonly encountered is that the top sealer fails to seal off the end portion properly due to the adhesion of froth to the top portion.
Accordingly, when the fluid to be filled has properties to readily froth, frothing is prevented by reducing the rate of discharge from the nozzle or pushing up the container to reduce the fall of the fluid to be filled.
However, the conventional packaging machine described has the problem that if the discharge from the nozzle is slowed down to prevent frothing, the filling time becomes longer. Even if it is attempted to diminish the fall of the fluid to be filled by lifting the container, the amount of lift of the container is limited.